1. Field of the Invention
This invention relates to the preparation of phenol-formaldehyde and melamine-formaldehyde resin-based binders modified with a urea-formaldehyde polymer containing at least 20% triazone and substituted triazone compounds (cyclic urea prepolymer) and to products prepared using the binders. More particularly, the invention relates to a prepolymer comprising urea, formaldehyde, and ammonia or a primary amine which, when added to a base resin, results in a useful binder or adhesive for the manufacture of numerous articles.
2. Description of Related Art
Phenol-formaldehyde resins and melamine-formaldehyde resins are standard resins used for many products. The choice of resin depends on the desired properties. Phenol-formaldehyde resins are strong and durable and relatively inexpensive, but are generally colored resins. Melamine resins are water clear but are more expensive. Hence they are generally used only for products whereby the color or pattern of the substrate is maintained with a transparent melamine protective coating or binder.